U.S. patent application number 14/237069 was filed with the patent office on 2014-07-24 for electro permanent magnetic system with magnetic state indicator.
This patent application is currently assigned to SCHUNK GMBH & CO. KG SPANN-UND GREIFTECHNIK. The applicant listed for this patent is Matteo Cipolla, Giuseppe Filosa, Daniele Messinella, Daniele Obori, Andrea Parolari, Albino Premoli. Invention is credited to Matteo Cipolla, Giuseppe Filosa, Daniele Messinella, Daniele Obori, Andrea Parolari, Albino Premoli.
Application Number | 20140202374 14/237069 |
Document ID | / |
Family ID | 44653390 |
Filed Date | 2014-07-24 |
United States Patent
Application |
20140202374 |
Kind Code |
A1 |
Filosa; Giuseppe ; et
al. |
July 24, 2014 |
ELECTRO PERMANENT MAGNETIC SYSTEM WITH MAGNETIC STATE INDICATOR
Abstract
An electro permanent magnetic system (10) for anchoring
ferromagnetic material, with magnetic state indicator (14),
comprising: an electro permanent magnetic module (12), a control
unit (11) for said electro permanent magnetic module (12), an
electrical connection system (13) between said control unit (11)
and said electro permanent magnetic module (12); a magnetization
indicator (14) for said electro permanent magnetic module (12)
associated with the electro permanent magnetic module (12);
characterised in that said magnetization indicator (14) is a
bistable indicator having two stable states; said magnetization
indicator (14) not requiring electrical power to remain in one of
said stable states; said magnetization indicator (14) being
electrically fed only in association with the magnetization or
demagnetization of said electro permanent magnetic module (12), to
pass from one stable state to the other of said two stable
states.
Inventors: |
Filosa; Giuseppe;
(Caravaggio (BG), IT) ; Obori; Daniele; (Mozzo
(BG), IT) ; Cipolla; Matteo; (Cassina De'Pecchi (Ml),
IT) ; Messinella; Daniele; (Caravaggio (BG), IT)
; Parolari; Andrea; (Caravaggio (BG), IT) ;
Premoli; Albino; (Gallignano Di Soncino (CR), IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Filosa; Giuseppe
Obori; Daniele
Cipolla; Matteo
Messinella; Daniele
Parolari; Andrea
Premoli; Albino |
Caravaggio (BG)
Mozzo (BG)
Cassina De'Pecchi (Ml)
Caravaggio (BG)
Caravaggio (BG)
Gallignano Di Soncino (CR) |
|
IT
IT
IT
IT
IT
IT |
|
|
Assignee: |
SCHUNK GMBH & CO. KG SPANN-UND
GREIFTECHNIK
LAUFFEN / NECKAR
DE
S.P.D. S.P.A.
Caravaggio
IT
|
Family ID: |
44653390 |
Appl. No.: |
14/237069 |
Filed: |
August 6, 2012 |
PCT Filed: |
August 6, 2012 |
PCT NO: |
PCT/IB2012/001502 |
371 Date: |
February 4, 2014 |
Current U.S.
Class: |
116/201 ;
116/204 |
Current CPC
Class: |
G01R 33/0088 20130101;
G01R 33/0058 20130101; H01F 13/00 20130101; G01R 33/028
20130101 |
Class at
Publication: |
116/201 ;
116/204 |
International
Class: |
G01R 33/028 20060101
G01R033/028; H01F 13/00 20060101 H01F013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 11, 2011 |
IT |
BG2011A000036 |
Claims
1. An electro permanent magnetic system (10) for anchoring
ferromagnetic material, with magnetic state indicator (14),
comprising: an electro permanent magnetic module (12), a control
unit (11) for said electro permanent magnetic module (12), an
electrical connection system (13) between said control unit (11)
and said electro permanent magnetic module (12); a magnetization
indicator (14) for said electro permanent magnetic module (12)
associated with the electro permanent magnetic module (12);
characterised in that said magnetization indicator (14) is a
bistable indicator having two stable states; said magnetization
indicator (14) not requiring electrical power to remain in one of
said stable states; said magnetization indicator (14) being
electrically powered only in association with the magnetization or
demagnetization of said electro permanent magnetic module (12), to
pass from one stable state to the other of said two stable
states.
2. A system as claimed in claim 1, characterised in that said
magnetization indicator (14) is positioned rigid with said electro
permanent magnetic module (12).
3. A system as claimed in claim 1, characterised in that said
magnetization indicator (14) is of electromechanical type.
4. A system as claimed in claim 1, characterised in that said
magnetization indicator (14) comprises an electric motor (22, 50)
connected to a rotatable two-colour cylindrical wheel (23).
5. A system as claimed in claim 4, characterised by comprising a
device (32) for measuring the current absorbed by said electric
motor (22, 50).
6. A system as claimed in claim 4, characterised by comprising a
positioning sensor (53) for said electric motor (50).
7. A method for implementing an electro permanent magnetic system
(10) for anchoring ferromagnetic material, with a magnetic state
indicator (14) for an electro permanent magnetic module (12),
characterised in that said magnetic state indicator (14) is
bistable; and by comprising the stage of electrically powering said
electro permanent magnetic module (12) to magnetize or demagnetize
said electro permanent magnetic module (12); electrically powering
said bistable magnetic state indicator (14) only in association
with the stage of electrically powering said electro permanent
magnetic module (12); said stage of electrically powering said
bistable magnetic state indicator (14) comprising the stage of
switching said bistable magnetic state indicator (14) from one
stable state to the other stable state.
8. A method as claimed in claim 7, characterised by comprising the
stage of rigidly associating said magnetic state indicator (14)
with said electro permanent magnetic module (12).
9. A method as claimed in claim 7, characterised by comprising the
stage of blocking the stage of electrically powering said bistable
magnetic state indicator (14) if a malfunction occurs during the
stage of electrically powering said electro permanent magnetic
module (12).
10. A method as claimed in claim 7, characterised by comprising the
stage of identifying one stable state from the other stable state
of said bistable magnetic state indicator (14) by means of a
two-colour element.
Description
[0001] The present invention relates to an electro permanent
magnetic system with magnetic state indicator and to a method for
implementing such a system.
[0002] Electro permanent magnetic clamping systems are appliances
intended for anchoring ferromagnetic material to enable mechanical
working by machine tools, or for use as gripping means in handling
and/or lifting systems.
[0003] An electro permanent magnetic clamping system consists of a
magnetic section (commonly known as an electro permanent magnetic
module), and of the relative electronic activation/deactivation
system (commonly known as the control unit).
[0004] The electro permanent magnetic module consists of a soft
iron support structure arranged to contain all the internal
components; one or more soft iron pole pieces, of shapes and
characteristics which can vary to adapt to the various
requirements; a variable number of permanent magnets variously
constituted and disposed; and one or more solenoids required for
module activation/deactivation.
[0005] Typically, a control unit consists of a bidirectional
controlled power rectifier which suitably powers the solenoids of
the electro permanent magnetic module; one or more control panels
to enable the operator to activate and deactivate the electro
permanent magnetic module; and an electrical connection system,
typically a cable to connect the control unit to the electro
permanent magnetic module.
[0006] An electro permanent magnetic module is a magnetic system
characterised by the following states.
[0007] Magnetized: stable state, does not require energy from the
control unit and remains indefinitely in the same state.
Unmagnetized: stable state, does not require energy from the
control unit and remains indefinitely in the same state. Transition
from unmagnetized to magnetized: limited duration state which
enables the magnet to be activated; during this stage the control
unit supplies energy to the magnetic module.
[0008] Transition from magnetized to unmagnetized: limited duration
state which enables the magnet to be deactivated; during this stage
the control unit supplies energy to the magnetic module.
[0009] From the aforesaid, a magnetic module of electro permanent
type does not require any form of energy to perform its function,
except for that provided during the activation/deactivation
stage.
[0010] The task of the control unit is to activate/deactivate the
electro permanent magnetic module by magnetization, demagnetization
or polarity inversion operations on a part or all of the permanent
magnets contained within the module.
[0011] Except for the time required to complete the two transition
operations, the control unit can be electrically disconnected from
the magnetic module.
[0012] Moreover, typically the activation/deactivation operations
are of very short duration, just a few seconds at the most. As
stated heretofore, the control unit and the magnetic module are
physically separate subsystems connected together by electric
cables; their interconnection varies on the basis of the type of
product.
[0013] It may be fixed, in the sense that the connection cables do
not present a connector enabling the magnetic module to be
disconnected manually from the control unit.
[0014] It may also be removable, in the sense that the connection
cables present one or more connectors enabling the magnetic module
to be disconnected manually from the control unit.
[0015] In any event, the type of connection lies outside problems
regarding the intrinsic system operation and is related only to
installation requirements.
[0016] With regard to installation on machine tools such as
millers, CNC machining centres and lathes, the magnetic module is
typically provided with a connection of removable type (plug-socket
connection) to ensure greater simplicity of installation and
prevent the presence of electric cables on the machine table.
[0017] This solution is moreover obligatory in machines provided
with automated pallet changeover systems.
[0018] Typically, the control units used for
magnetizing/demagnetizing the magnetic modules are provided with a
system for visually indicating the state of the magnetic module via
lamps.
[0019] Knowledge of the magnetic state is of fundamental importance
in ensuring operator safety, for example during the operations
involved in positioning pieces on the magnetic module, in starting
machining operations, etc.
[0020] The salient characteristics of these visual display systems
are the following.
[0021] Usually, they are not installed on the module itself. This
does not facilitate easy legibility of the magnetic state during
the positioning operations.
[0022] In the case of removable connection magnetic modules, as the
information of the module magnetization state resides in the
control unit, removing the connection does not ensure information
consistency. In other words, disconnecting the control unit from
the magnetic module makes it impossible to recognize the magnetic
state of the module in environments in which more than one magnetic
module and/or more than one control unit are present. In the case
of non-removable connection systems (for example lifters),
indication of the magnetization is a function of the presence of
electrical energy; lack of energy banally causes extinguishing of
the indicator lamps.
[0023] An object of the present invention is to provide an electro
permanent magnetic system with magnetic state indicator able to
store the information relative to the magnetic state in the system
itself.
[0024] Another object is to render the magnetic state information
available to the user via a rapid consultation system.
[0025] A further object is to not require energy for indicating the
magnetic state of the system.
[0026] These and other objects are attained according to the
present invention by an electro permanent magnetic system intended
for anchoring ferromagnetic material, with magnetic state
indicator, and by the relative method for its implementation, in
accordance with the accompanying claims.
[0027] Further characteristics of the invention are described in
the dependent claims.
[0028] This solution has various advantages compared with solutions
of the known art.
[0029] The proposed solution provides a bistable magnetization
indicator of the electro permanent magnetic module, the task of
which is to associate with each of the two available stable states
the corresponding magnetized and demagnetized states of the
magnetic module, without the need to maintain it electrically
powered.
[0030] By virtue of the fact that it does not require electrical
powering, it can be positioned rigid with the electro permanent
magnetic module even in the case of removable interconnections.
[0031] Sensors are also present to ensure that the information
shown by the indicator is true and correct. In this respect, if a
malfunction occurs during the magnetization and demagnetization
stages, the indicator does not change state.
[0032] The characteristics and advantages of the present invention
will be apparent from the ensuing detailed description of one
embodiment thereof, illustrated by way of non-limiting example in
the accompanying drawings, in which:
[0033] FIG. 1 shows schematically an electro permanent magnetic
system with magnetic state indicator, in accordance with the
present invention;
[0034] FIG. 2 shows schematically a magnetic state indicator, in
accordance with the present invention;
[0035] FIG. 3 shows schematically the electrical scheme of a
magnetic state indicator, in accordance with the present
invention;
[0036] FIG. 4 shows schematically an interface between the control
system of the electro permanent magnetic system and the electro
permanent magnetic module containing the magnetic state indicator,
in accordance with the present invention;
[0037] FIG. 5 shows schematically a magnetic state indicator, in
accordance with a variant of the present invention.
[0038] With reference to the accompanying figures, an electro
permanent magnetic system 10 with magnetic state indicator, in
accordance with the present invention, comprises an electronic
control unit 11 for activating an electro permanent magnetic module
12, and an electrical connection system 13 between the control unit
11 and the electro permanent magnetic module 12. It also comprises
a magnetization indicator 14 associated with the electro permanent
magnetic module 12, and an interface 15 between the control unit 11
and the electro permanent magnetic module 12.
[0039] The electrical connection system 13 comprises both the
electrical power cables of the electro permanent magnetic module
12, required for its magnetization and demagnetization, and the
communication cables between the interface 15, the electro
permanent magnetic module 12, and the magnetization indicator
14.
[0040] The operation of verifying the correct magnetization and/or
demagnetization is usually carried out by the control unit 11, for
example by analyzing in various ways the main characteristics of
the current absorbed by the magnetic system during the transient
magnetization and demagnetization stages. Analysis of the mean
current, of the peak current, of the charge fed, are all known
methods which enable the control unit 11 to correctly know the
magnetization state.
[0041] The information relative to the state of the magnetic module
12, however obtained, is therefore present in the control unit
11.
[0042] According to the present invention, the control unit 11
transfers the information to the magnetization indicator 14 via the
electrical connection system 13.
[0043] The magnetization indicator 14 comprises a connector 20 for
the electrical connection system 13, an electronic control card 21,
a stepping motor 22, and a rotatable two-colour cylindrical wheel
23 connected to the motor 22, one half of the wheel being of one
colour and the other half of another colour.
[0044] The electronic control card 21 comprises an input connector
20 for the control signal originating from the electrical
connection system 13; a diode bridge rectifier 30 connected
directly to the connector 20; a command circuit 31 for the stepping
motor 22, a measuring device 32 for the current absorbed by the
stepping motor 22, connected in series between the rectifier 30 and
the command circuit 31; a position sensor (or several sensors) 33
for the stepping motor 22; and a polarization sensor 34 for the
control signal present at the terminals of the connector 20.
[0045] It also comprises, for the card 21, a control circuit 35
which communicates with all the elements of the electronic control
card 21.
[0046] The interface 15 comprises a control circuit 41 for the
interface 15 itself, communicating with the control unit 11; a plan
presence verification circuit 42 (carry out in known manner); a
control circuit 43 for the magnetization indicator 14; and a
circuit 44 for verifying the current absorbed by the magnetization
indicator 14.
[0047] Preferably, the magnetization indicator 14 is rigid with the
magnetic module 12 by being fixed to it or positioned in its
vicinity, such that the operator using the magnetic module 12 is
conscious of the state of this latter.
[0048] Alternatively it can also be separated from the magnetic
module 12 and have only an electrical connection with the interface
15.
[0049] An advantageous embodiment of the magnetization indicator 14
has been represented and described, however other embodiments are
possible.
[0050] For example, a magnetization indicator 14 can be formed as
in FIG. 5 and comprises a linear stepping motor 50, an indication
cylinder 51 connected to the motor 50, an electronic control
circuit 52 for the indicator, a position sensors 53, and a
connector 54 for connection to the interface 15.
[0051] The magnetization indicator 14 can also be formed in other
ways, provided it is of bistable type, i.e. comprising two stable
states, and does not require electrical power to remain in the
stable states. The electrical power for the magnetization indicator
14, which is provided in association with the feed to the electro
permanent magnet for changing its magnetization state (and is
normally supplied after magnetization or demagnetization of the
electro permanent magnet), serves only for passing from one state
to the other. For example it can be in the form of a bistable
relay.
[0052] The operation of the system according to the invention is
evident from that described and illustrated, and in detail is
substantially as follows.
[0053] On receiving a magnetization and/or demagnetization request,
the control unit 11 initially verifies that the magnetic module 12
is connected to it by the electrical connection system 13.
[0054] This is done by the plan presence verification circuit 42,
by interrogating the control circuit 41.
[0055] If the response is positive, the control unit 11
electrically powers the solenoids of the magnetic module 12.
[0056] As already stated, for example, from the analysis of the
current absorbed by the magnetic module 12 during the transient
stage, the control unit 11 is able to determine the correct
magnetization or demagnetization state of the module 12.
[0057] Hence having determined the state of the magnetic module 12,
the control unit 11 transmits the information to the indicator 14
via the interface 15.
[0058] Specifically, the control logic 41 activates the control
circuit 43. The circuit 43, by way of the electrical connection
system 13, provides a suitably polarized voltage to the indicator
14.
[0059] On analyzing the voltage received, the indicator 14 is able
to recognize the direction of the voltage electrical polarization
by virtue of the polarization sensor 34.
[0060] By using the information obtained from the sensor 34 and
from the sensors 33, the management circuit 35 is able to determine
a correct operating strategy for the stepping motor 22 by the
command circuit 31 for the stepping motor 22.
[0061] According to the correct movement strategy, the motor 22
rotates through 180.degree. to show the appropriate colour
associated with the magnetic state, by means of the two-colour
wheel 23 (red: unmagnetized, green: magnetized).
[0062] The current measuring device 32 detects any problems arising
during its movement and immediately interrupts it.
[0063] During the movement stage, the magnetization indicator 14
absorbs a specific current which is measured by the circuit 44
verifying the current absorbed by the magnetization indicator
14.
[0064] This information enables the control circuit 41 to determine
the indicator transition time and to prohibit operation of the
control unit 11 until this transition has terminated.
[0065] After the appropriate movement of the two-colour wheel 23,
the magnetization indicator 14 lies in the waiting state.
[0066] Removal of the connection 13 does not modify the positioning
of the two-colour wheel 23 in any manner, hence the information
associated with the state of the magnetic module 12 is available,
unalterable, and does not require energy for its display.
[0067] Moreover, the information relative to the magnetic state of
the module 12 is always unequivocally associated with it, a
condition which is not necessarily true in the case in which the
information relative to the state resides in the control unit 11
and the connection system 12 is disconnected from the magnetic
module.
[0068] The constituent circuits of the electro permanent magnetic
system with magnetic state indicator according to the present
invention will not be further described in detail as an expert of
the art is capable of implementing them from the teachings of the
preceding description.
[0069] In practice, the materials used for the electro permanent
magnetic system with magnetic state indicator, and the dimensions,
can be chosen at will according to requirements and to the state of
the art.
* * * * *